Effects induced by single and multiple dopants on the transport properties in zigzag-edged graphene nanoribbons

Abstract

The effects of boron and nitrogen doping on the transport properties of zigzag-edged graphene nanoribbons ͑ZGNRs͒ with antiferromagnetically coupled edge states are investigated by first-principles electronic structure combined with a nonequilibrium Green's function technique. Specifically, the effects produced by single and multiple impurities as a function of their distance from the edges are analyzed. It is found that the introduction of single B or N atoms induces bound states and quasibound states in ZGNRs, which can be observed as dips or peaks in the electron transmission function. In particular, the transmission channel associated to the edge states is strongly suppressed when the impurities are close to the edges. Multiple impurities in general interfere and modify further the transmission function. However, if the impurities are placed at positions such that the associated bound and quasibound states appear at opposite sides of the Fermi level, then the transmission can be rationalized as a simple superposition of the transmission function of individually doped ribbons. Finally, an interesting situation appears for B and N codoping, since fully spin-polarized transmission peaks are generated at energies corresponding to the ribbon gap. This offers the hope of using such nanoribbons for low-bias spin-polarized tunneling in spintronics applications.

Spin transport in highern-acene molecules

“…One of the HOMOs is localized mainly on the hydrogenated carbon atoms at one edge of the molecule, while the other HOMO is localized on the opposite edge. These two degenerate molecular orbitals extend in a zigzag-like symmetry along the length of the molecule as indicated by the dashed lines in Fig 1. These states are similar in nature to the edge states found in graphene nano-ribbons [34]. The lowest unoccupied molecular orbitals (LUMOs) are the corresponding empty spin-split orbitals, so that the HOMO-LUMO gap is an exchange split gap.…”

CO2 adsorption on Fe-doped graphene nanoribbons: First principles electronic transport calculations

“…However, the effect of the foreign atom doping on the structural and electronic properties of the graphene strongly depends on the location of the dopants with respect to the edges. [57][58][59] The transmission spectrum changes drastically when the Fe-atom is present in the system; the Fe atom adsorption results in considerably reduction of electron transmission as compared to pristine graphene (compare solid black curves in Figs. 2(a) and 3(a)).…”

Atomistic simulations of the implantation of low-energy boron and nitrogen ions into graphene

“…Not surprisingly, several theoretical studies on hybrid C-B/N systems [13][14][15][16][17][18] have recently been carried out. Particular attention has been paid to graphene nanoribbons [19][20][21][22][23][24]. Although it is possible to introduce B/N atoms into graphene during synthesis [9][10][11][25][26][27][28], not many studies have investigated the possibility of selectively introducing B/N impurities into graphene after growth, while post-synthesis doping may be an alternative way to create graphene-based functional materials.…”